The carbohydrate-conversion industry is large and rapidly increasing in size. Currently, about 100 million tons of carbohydrates are fermented annually, primarily to provide fuel-grade ethanol. This number is predicted to triple in the next decade.
Millions of tons of carbohydrates are also fermented every year to provide food and feed products, such as citric acid and lysine. Also large and increasing is fermentation to produce other products, such as monomers for the polymer industry, e.g. lactic acid for the production of polylactide.
Fermentation media typically include, in addition to carbohydrates and/or another carbon source, other nutrients and factors such as nitrogen sources, minerals, vitamins, and growth factors. In some cases, fermentation media comprise well identified chemicals. In other cases, various preparations (e.g. yeast extract or tryptone broth) are incorporated without fully understanding the effect of each component in the preparation. Some of those preparations result from natural sources, such as extracts. Some of those preparations are of relatively high cost.
With the advent of molecular biology techniques, a new generation of industrial fermentation, also known as conversion, based upon genetically modified microorganisms has emerged. In some cases these microorganisms rely upon inducible promoters for induction of a specific gene. Some of the inducible promoters respond to specific sugars.
Although conversion of lignocellulosic material to carbohydrates via enzyme-catalyzed and/or acid-catalyzed hydrolysis of polysaccharides and pyrolysis of lignocellulosic material have been previously described, industrial scale application of the proposed technologies has presented technical problems which remain to be overcome. Hydrolysis of hemicellulose is relatively easy, but hydrolysis of cellulose (typically more than 50% of total polysaccharides) is more difficult due to its partial crystalline structure.
Acid hydrolysis of lignocellulosic material was considered and tested as a pretreatment for enzymatic hydrolysis. Alternatively, acid could be used as the sole hydrolysis catalyst, obviating the need for high-cost enzymes. Most of the efforts focused on sulfuric acid and hydrochloric acid (HCl), with preference for the latter.
This application refers to various solvents defined in terms of Hoy's cohesion parameter Delta-P and/or Delta-H. By way of review:
Delta-P is the polarity related component of Hoy's cohesion parameter and delta-His the hydrogen bonding related component of Hoy's cohesion parameter.
The cohesion parameter, as referred to above or, solubility parameter, was defined by Hildebrand as the square root of the cohesive energy density:
  δ  =                    Δ        ⁢                                  ⁢                  E          vap                    V      where ΔEvap and V are the energy or heat of vaporization and molar volume of the liquid, respectively. Hansen extended the original Hildebrand parameter to a three-dimensional cohesion parameter. According to this concept, the total solubility parameter, delta, is separated into three different components, or, partial solubility parameters relating to the specific intermolecular interactions:δ2=δd2+δp2+δh2 in which delta-D, delta-P and delta-H are the dispersion, polarity, and Hydrogen bonding components, respectively. Hoy proposed a system to estimate total and partial solubility parameters. The unit used for those parameters is MPa1/2. A detailed explanation of that parameter and its components can be found in “CRC Handbook of Solubility Parameters and Other Cohesion Parameters”, second edition, pages 122-138. That and other references provide tables with the parameters for many compounds. In addition, methods for calculating those parameters are provided.